It was narrated from 'Aishah that the Messenger of Allah (ﷺ) said:
"The best of your provision is what you earn, and your children are part of what you earn. " (RU)
English reference (RU): Vol. 3, Book 12, Hadith 2290 (RU)
Arabic reference (RU): Book 12, Hadith 2378 (RU)